I'm guessing you've already played with sidetone, advanced noise control and hd intercom settings?
Does your wife experience the same issue? If not, you may have a dodgy unit.
I've a 20s which I have used with the flip of my Neotec open and shut, and can still talk without the wind being a problem for the other user. Do you have any different sponges to try on the microphones? Is it possible to re-site them a bit more out of the draught?